Various Methods to Query Public IP on Linux Systems

In Linux systems, querying the public IP (outbound IP) is a common network management requirement. This article will introduce three methods to query the public IP using the curl, wget, and dig commands, along with code examples and considerations.

Using the curl Command

By calling third-party IP query services to obtain the public IP, the following concise commands are recommended:

# Basic query
curl ifconfig.me
# or
curl icanhazip.com
# or (JSON format output, includes more information)
curl ipinfo.io/json

Output Example:

192.0.2.123  # Only IP
# or JSON format
{
  "ip": "192.0.2.123",
  "city": "Beijing",
  "region": "Beijing",
  "country": "CN"
}

Using the wget Command

If curl is not installed on the system, wget can be used as a substitute:

# Basic query
wget -qO- ifconfig.me
# or
wget -qO- http://ipecho.net/plain

Output Example:

192.0.2.123

Using the dig Command (DNS Query)

Querying the IP through OpenDNS’s DNS service:

# DNS query
dig +short myip.opendns.com @resolver1.opendns.com

Output Example:

192.0.2.123

Considerations

1. Network Dependency: The above methods require the device to access the internet; in an internal network environment (such as NAT), the router’s public IP will be returned.
2. Service Selection: It is recommended to use<span>ifconfig.me</span> or <span>icanhazip.com</span>, which are fast and stable.
3. Script Integration: The commands can be embedded in scripts, for example:

PUBLIC_IP=$(curl -s ifconfig.me)
echo "Current public IP: $PUBLIC_IP"

Method Comparison

Method	Command Example	Applicable Scenarios
curl	<span>curl ifconfig.me</span>	Quickly obtain IP
wget	<span>wget -qO- ifconfig.me</span>	No curl environment
dig	<span>dig +short myip.opendns.com...</span>	Scenarios requiring DNS queries

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